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-   -   Exhaust vs Timing, something else? (http://www.toyota-supra.info/forums/mkiii-supra/16363-exhaust-vs-timing-something-else.html)

Krem 03-16-2010 12:17 AM

Exhaust vs Timing, something else?
 
So car has been degrading in performance for last couple of months. She used to have a nasty noise around 4000rpm and has moved down to ~3200rpm now. Noise sounds like a turbo spooling with a bad bearing, except I don't have a turbo.. After running warm/hot and parking for 15~20 min, she won't want to start back up.. she'll turn over, drop idle VERY low and stall out, then I can smell a funny exhaust smell in the cab. I can get her started if I give it a good amount of gas while turning her over to prevent the low rpm idle. Finally, the headers have been glowing red the past couple of nights after a 12 mile drive home from work where she sits all day.

I'm thinkin it's the exhaust system somewhere as the symptoms first began when I got my car back from a trial and error diagnostic repair where some mechanic pulled the o2 sensor and they did my timing. Not sure which timing they did, but I do know they had to replace my distributor and open the timing case, so another reason I am leaning towards exhaust system more so than timing. Wondered if anyone could confirm, deny or propose a more likely cause. :x:

cre 03-16-2010 12:54 AM

I'm leaning more toward the timing belt and a shot tensioner pulley.... Check the mechanical timing as shown in the MKIII FAQ.

Exhaust is easy enough to check... disconnect it right before the cat. ;)

So, no codes?

Krem 03-17-2010 03:27 AM

Thanks Cre, guess I get to dig back in the timing case... maybe this time I'll just leave it off, looks much more bad ass with the cam gears visible anyways IMO. Really hope to get this fixed, tired of being out accelerated by a Ford Festiva/Fiesta.. oh, and yea... sorry, but no codes :(.. which is why I refused to let someone hook up a diagnostic machine to my car for $90 to pull the codes that aren't there. Yay for 1960's troubleshooting eh?

btwilson86 03-17-2010 04:07 AM

Quote:

Originally Posted by Krem (Post 80264)
maybe this time I'll just leave it off

Oh, please don't. Even though these are non-interference engines (thank god), the potential for snapping your timing belt or ruining the teeth on your cam gears is not worth the look (IMO anyway)

I feel like I've been saying this too much lately in a few threads, but check your ignition timing after you check your valve timing. I'm pretty sure fairly advanced ignition timing (maybe it's retarded timing, don't remember for sure) could cause high exhaust gas temps (hence the red headers). Like I said though, check it after you set your valve timing or you'll just have to do it twice

Krem 03-17-2010 04:53 AM

thanks for the tips BT.. that is def. why I mentioned that in my post... wasn't sure if it was a good idea or not despite appearance... guess I know better now and have you to thank for that :D. So I'll give the timing a look at this weekend. Just hope she'll be ok for travel back and forth this week..:x:

cre 03-17-2010 12:42 PM

Retarded timing = high EGT. Advanced timing = more heat transferred into the block and thus lower EGT.

Green7mgte 03-17-2010 02:55 PM

off topic but you can get clear cam covers.

Krem 03-17-2010 08:06 PM

Quote:

Originally Posted by cre (Post 80275)
Retarded timing = high EGT. Advanced timing = more heat transferred into the block and thus lower EGT.

could this be why after driving several miles I smell a lean exhaust smell in my cabin?

cre 03-18-2010 12:32 AM

Quote:

Originally Posted by Green7mgte (Post 80277)
off topic but you can get clear cam covers.

Cam covers? Ack... not very pretty with all the oil getting thrown around and all... ;)

Quote:

Originally Posted by Krem (Post 80285)
could this be why after driving several miles I smell a lean exhaust smell in my cabin?

A smell in the cabin is more likely due to a bad hatch seal or a leak elsewhere in the trunk.

Green7mgte 03-18-2010 02:39 AM

oops i ment timing cover. just forget im here..
"slinks into the back"
http://www.horsepowerfreaks.com/perf.../Timing_Covers


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